^ I read many threads and watched many youtube videos before doing mine. Education is key to any task IMO. The most helpful thread talked about removing the seam-sealer before rolling. I wish I had the links to share, sorry I don't, but if you roll the fenders without removing the seam sealer you will be forever encasing it between the two pieces of metal and you may not get all of the roll or clearance you wanted/needed. Once removed, even though I don't live in the north, I taped off and coated the scratched up back side of the area with some under-coating. This might sound counter-intuitive, but trust me, that seam sealer is THICK right there, and a coat or two of under-coating is much thinner. After that, I thought the actual fender rolling was easy yet mundane compared to removal of the seam sealer. Seam sealer removal was more instant gratification where as heating up the metal (without blistering the paint) and using the rolling tool took forever and was so boring.
I did mine probably 18-24 months ago and when I plan to do my spring cleaning/waxing I hope when I remove the rear wheels everything looks the same as it did when I completed the job. *crossing fingers* It looked fine last year, but this past winter was brutal, even in Memphis.